Tool trigger switch



April 7, 1959 P. H. WINTER ETAL TOOL TRIGGER SWITCH Filed Now/.29, 1957 INVENTORS PAUL H WINTER MARK IV. RUSSELL ATTORNEYS United States Patent TOOL TRIGGER SWITCH Paul H. Winter and Mark N. Russell, Syracuse, N.Y., as-

signors to Pass & Seymour, Inc., Syracuse, N.Y., a corporation of New York Application November 29, 1957, Serial No. 699,555 7 Claims. (Cl. 200-157) This invention relates to a trigger switch for tools and more particularly to such a switch making use of a large, hollow, moulded trigger forming the closure for the switch housing. 1

It is a general object of the present invention to provide a novel and improved construction of trigger switch for tools having enhanced appearance, operating characteristics and manufacturing facility.

More particularly it is an object of the invention to provide a trigger switch for tools including an open top housing having stationary and movable switch contacts therein, a trigger slidable through the top housing opening and accommodating within itself, operating mechanism for the movable contacts, and a frame element secured to the housing mounting a fulcrum for said mechanism and serving to retain the housing, trigger and movable switch parts in assembled relation.

One important object of the invention is to provide a switch having a trigger element of hollow moulded construction, large size and rectangular cross-section whereby it not only serves to close the mouth of the switch housing but is itself hollow to accommodate actuating mechanism for the switch.

Another important object of the invention consists in the use of an operating lever, for moving the switch contacts, having arms extending oppositely from the lever fulcrum for engagement respectively with an actuating abutment in the trigger and a trigger return spring also housed therein and both ofiset laterally from the said fulcrum.

A further important object consists in the arrangement within the trigger of the actuating abutment and the return spring whereby the latter is compressed through the actuating lever by manual movement of the trigger.

Still another object of the invention consists in extending the operating lever fulcrum pin across the width of the trigger, supporting the same in frame brackets straddling the trigger and slotting the trigger shell to slide over and be guided by said pin.

An important feature of the invention resides in the use of guiding arms in cooperation with grooves and walls on the trigger to guide the latter for straight movement into the housing.

Other and further objects and features of the invention will be more apparent to those skilled in the art upon a consideration of the following specification and accompanying drawing wherein is disclosed a single exemplary embodiment of the invention with-the understanding that such modificationsmay be made therein as fall within the scope of the appended claims without departing from the spirit of the invention- In said drawings:

Fig. 1 is an end elevation of a tool trigger switch constructed in accordance with the present invention, the locking pin being in the inactive position;

Fig. 2 is an elevation of the switch, looking from the locking pin side;

Fig. 3 is central longitudinal section on an enlarged 2,881,292 Patented Apr. 7, 1959 scale, taken on line 3-3 of Fig. 1, looking in the direction of the arrows showing the parts in solid lines for the oif position and in dotted lines for the on position;

Fig. 4 is a side elevation of the trigger separated from the switch;

Fig. 5 is a longitudinal section through the trigger taken on line 5-5 of Fig. 4, and

Fig. 6 is a bottom plan view of the trigger.

Trigger switches of small size and capacity such as used in hand drills, portable power saws and in many other hand held power tools have not heretofore been entirely satisfactory from the standpoint of simplicity of construction, reliability of operation, ease of application to the tool, and facility of operation. The present invention is directed to a trigger switch which solves the prob lems not satisfactorily solved by existing devices. The switch makes use of the large, molded, trigger of rectangular cross-section protruding through the open top of the switch housing, into which it partially telescopes when pulled to close the circuit.

Referring now to the drawings for a better understanding of the invention, Figures 1 and 2 illustrate the completely assembled device, where is seen at 10 a switch housing of the molded type, generally rectangular in plan, elevation and end views and closed on all sides but the top 11. Within this housing as seen in Figure 3 is a large irregular shaped chamber 12 for the switch mechanism. The open upper end of the housing is closed by the trigger 14 seen in side and end elevations in Figures 1 and 2 in its assembled relation, and in Figures 4, 5 and 6 alone, showing it to be molded from a suitable insulating plastic. Its outer end or top 15 is suitably curved to cooperate with the trigger finger for ease in pressing the trigger which slides rectilinearly into and out of the housing for a distance limited by the stop shoulders 16 and 17 therein. The stroke is quite short as depicted in Figure 3, for its relaxed and pulled positions are shown respectively in solid and dotted lines therein.

The trigger is rectangular in horizontal section and of uniform width and length throughout its height, except at the bottom, where end flanges 18 and 19 not only serve for guidance along the end walls 20 and 21 of the recess or chamber 12 but, are overhung by edges of the insulating cover plate 23, as seen at 24 and 25, to maintain the trigger in position and limit its outward movement. The flanges also cooperate with stop surfaces 16 and 17. In order to hold the housing 10, .the cover plate 23 and the trigger in assembled relationship, a one piece sheet metal stamping is called into play, comprising a pair of vertical side rails 27 and 28 connected by transverse flat members 29 at the right end and 30 at the left which overlie the ends of the cover plate 23.

Fastening devices, such as shown at 31 and 32, depend and are arranged to be deformed, as shown in Figure 1, for engagement with abutments on the housing 10 to secure the frame and the cover plate thereto in at least three places insuring a rigid assembly. On the right, as viewed in Figure 1, a narrow wing or tab 33 projects upwardly from the rail 28 near its center and is laterally offset as shown to closely engage the flat side 34 of the trigger. On the other side a substantial upward extension 35 is in alignment with the rail 27 from which it protrudes and is provided with a depressed border area 36 which not only rigidities it but causes it to closely engage the side 38 of the trigger. Thus the trigger is guided Well above the surface of the housing by the wing and border. It is further guided against lateral movement or canting by tongue 39 extending integrally upwardly from the part 29 of the frame and having parallel edges which cooperate with the walls 40 of a groove in one end wall 'of the trigger, as clearly seen in Figures 1 and 3. All upstanding frame parts are of less height than the trigger so that yond its finger surface 15.

The actual switch mechanism is of the more or less cmiventionahsnap variety including the daterally. spaced sstationary contacts 4-2 oft-a-pain mounted: adjacent the =floor'43'of thexhambenin Tithe housing and appropriately flaredrtoa-receiye the. swinging." bridging: contacts element 44 of conventional construction, swinging about trunnions, :14. not-shown; fulcrumedsinmotches .45 acentrailly located in the upper edges of the sidel.walls ofthehousing. A sheet metal switchtaetuator 46IlS;:fl1lCIUIIld on cross pin 47 -".:extendingvfrom:wing;33 tO5Wl11gja35 above the side rails 27 ;and 280i thezframe; 'Anzarrn 483011 thisactuator has a artiallygcircular :head .49. engaging in asocket in insulatingzzhutton SQawhose reduced.1cylindrical: lower'end is Qused'jn theupper few; coils .-of.-lhelicalspring 51-,whosc owenend fi s. overipmiectionfilin the;;U.-shaped swingcustomaryr;manner; In the position: illustrated in, Figure -3 -the -swi t ch ;is in the-open position with the:;swinging contact-gabutting,againstpfixed stop 54; and thezspring wfover center--to the, left. i If theaactuator-is swung so that part 49 carries thespringover center the contact yoke promptly swings-to the left, bridging stationary contacts 42 and; closing the circuit between suitable, connectors, not

,of the .switch asviewedin ,Figure 2.

-;to the long:pivot pin4 7 by beingconfined between the I, walls 56.0f' the vertical central slot in the trigger and is in scribed,; and1ateral arms 52 and 60, generally oppositely disposed andgroughly on ,a n axis-atright angles to arm 48.

s topne --by,,arcuate sector 61;.which bears at .alltimes againstthesabutment-surface 62 at the top of the left portion of, slot 56 ,wherebydownward movement, or a ism-when thewlattermispulled.noneof them. projects beforce s othatit can return the. trigger. and vsnapthe switch to the"ofi position when the trigger is-released.

Over and beyond its function of supporting one end of the fulcrum -pin.'47 .the enlargedarea ofwing 35 provides .mxip on ae ;M an l':pr0vides for the .Snapactiomin the shown, for conductors which'enter; through the left end a rigid support forlocking pinassembly 80, shown in Figures l and 2;" This includes a sleeve 81 having one end secured to 35 around a hole therein, and housing a helical return spring, not shown, and the button 82 telescopically arranged therein andiheld to .theinormal. released position :by the-aspring;:TheJSideI-WaIl 138 of thentrigger has an 2 opening'l84; therein. so;positioned that; with the .trigger retracted an extension pin, not shown, on the-button is "t =-m.0red-.- into,;h0le:r84cso "that thettrigger may be .released by the-:ifinger'and yetuheldzrfrom moving .to itserelaxed position hy engagement of the pinwwith theyloweri wall of hole 84. To prevent the retraction spring for locking button ,82;; from withdrawing the pin; from hole 84 the f pin isfitted :with; an enlarged head, the-undersideofwhich Theswitchactuators46 is centrall-ypositioned in respect ,efiect a;dual bell-crankhaving thearm 4-8, already dewithdrawal, The,switch,will thus.,remain closed until pre sure'i applied to theatrigger to retract-it slightly to allow the ;button--retraction spring'touwithdraw the ilocking pin as its; head;hecomeszreleased; from thewlower Armgsfliflxterids to thedeftaas viewed in, Figure 3-,- and H -fpulling".,of the,trigger,;rotates the actuator in a counterclockwise -direction-and-moves theswitch to the on ,.,,position.

To pcrmiLsu'ch f pull of the trigger, as well as to facilitateswitch, assembly, the, two sides of the trigger are .yertically slottedat 64,:as best seen in Figure 4. The

,widthof these vertical slots, is ,such that the sides sub- ,Mstantially engagevpivot pin.47 for the actuaton As seen 'infigures 3,,4, andtfislots, 64 are widened attheir lower 1 ends at 65 fora length at. least equal to the stroke of the trigger and here thewallsstraddle ,those of ribs 66- pro- -,-jecting inwardlyjrom eachhousing sidewall. These ribs run to the top, of the, housing and-accommodate portions not the notches -in,which the, trunnions of the movable Contact elementfulcrum.

13y jhaving thet trigger guided at itsalower endover ribs J j661aswell as-above its center over pivot pin 47-, any

canting about :a transverse.axis, due toeccentric pressure the finger-;-surface .15,.is:prevented-: Transverse cants f wings ,33 and. ,3 5;with theside' :walls of the trigger.

., Theyirighta arm on the, switch actuator is provided ,ithamupturned portionr68=-having-an arcuate upper end slower? end of the helical trigger return'spring 70 housed nrvertical b'orez*71-' in the right end of the trigger.- The :'WhiCh= cooperateswitha dished follower69 fitted into the --upper end=of-the spring iscompressedagainst the top 72 of bore 11; and in the normal or relaxed iposition, il-

wall of hole 84. flhettrigger may-nowybe released and will be. automatically, returned to its .relaxed'position.

=Thelocking piu arrangement;and-.assemblyjis the invention ofkobert OfMara; and :iorms the subjectmatter of; United States patent I application SerialQNumber 698,139, ;fil ed November 22,. 19517,; andwreferenceshould be had to that application for fulldetails' of the construction, assembly and-operationof the locking pin.

For certain purposes the locking pin may be undesirable and can-easily be omitted in the switch assembly operation,

:without detracting-from the improved characteristics of I the triggenswitch, such ;,as the largecross-section, rectangular, insulating trigger, thee-telescopic relationship of trigger and switch housing, the unique arrangement of the trigger return, spring and the-housing of the switch actuatorv in the trigger.

-H aving--thus-.describ ed our--invention,,what we; claim as novel and desiretosecureby Letters-Patent of the United States is:

Sing-:is-takemcareaofas wasexplained iIlggCOHIlCCliOH with ongue 3 9. and groove walls;.40 aswell as thecooperation a..fulcrum pin extending between said wings, a flat actu- :l. In= a,-,;trigger;-rswiteh,,in-combination, anopen top housing h ving a; ch-amber containing stationar-y contacts, acontact movable for two-wayenap, cooperation with said stationary contacts, agriggerrectilinearly slidable toward .said,.-charnber-;--.when -pulled, wings extending from said hqusingalongside opposite exposedfaces of said trigger,

ating lever pivoted on said pin and having an overcenter- 7 spring; EOilnfiQElOllxtOcSflid 1 movable contact,- laterally and oppositely disposed arms on saidlever; .a pin accommodating slotinsaid trigger,==means :in said trigger tocenter said lever on the pin,an-abutrnent insaidtriggerto engage oneofsaidarms'tosn'ap the switch when the trigger is pulled 'toward the-housing,= a spring in -triggerbearingon the other lever arm so-asto be loaded-when the trigger is pulled, and said' spring acting to return the trigger on its release and to,snap the switch'contact in the opposite direction.

'2. The switch of claim 1 inwhichlsaidnwings are part .ofa combined-frameand, housing top. closure supporting the trigger and means securing said frameto said=housing to partially closesaidopen top.

3. The switch of claim 2 in which the trigger has lateral ledges on its end facing the chamber and said frame and top closure has means overhanging said ledges to retain the trigger in the housing.

4. The switch of claim 2 in which said trigger has a longitudinal groove in a wall between said exposed faces and a tongue on said frame extending longitudinally into said groove to guide the trigger.

5. The switch of claim 1 in which one of said wings mounts a locking pin assembly with its axis normal to said wing, said assembly including a spring retracted pin, said trigger face adjacent said wing having a hole therethrough adapted for alignment with the pin axis when the trigger is retracted to receive the locking pin to hold the trigger pulled.

6. In a trigger switch, in combination, a housing having a chamber containing stationary and swinging snap contacts, an actuator having a lever connected to the snap contacts by an overcenter spring and a pair of arms directed toward opposite sides of said lever, a pivot for said actuator fixed to said housing, a trigger slidable in respect to said housing, an abutment in said trigger to engage one of said arms when the trigger is pulled toward the housing to snap the switch, and a coil spring between the other arm and a second abutment in said trigger so as to be compressed as the trigger is pulled.

7. The switch as defined in claim 6 in which the spring in the trigger is of suflicient strength to return the trigger to its repose position and thereby snap the switch again.

References Cited in the file of this patent UNITED STATES PATENTS 2,211,815 Hansson Aug. 20, 1940 2,277,555 Meuer Mar. 24, 1942 2,366,474 Bentley Jan. 2, 1945 2,473,848 Baxter June 21, 1949 2,552,471 Watkins May 8, 1951 2,576,771 Bentley Nov. 27, 1951 2,775,711 Kommer Dec. 25, 1956 2,810,031 Hellstrom Oct. 15, 1957 

